1. Field of the Invention
The present invention is in the field of window devices, and more particularly pertains to a window device of the type which is capable of being tilted inwardly about a horizontal pivot axis coincident with the lower edge of the window sash for venting, and also pivotal about a vertical axis so as to function in the manner of a casement window, particularly to provide access to the exterior of the window from the interior of an enclosed space so as to facilitate cleaning.
2. The Prior Art
Windows of the tilt and turn type have come into progressively increasing use in office buildings, institutions and like applications. Window constructions of the type described are shown in United States patents as follows:
______________________________________ 2006,004 Wenzel June 25, 1935 2866,635 Frank Dec. 30, 1958 2969,566 Mayer Jan. 31, 1961 3004,304 Frank Oct. 17, 1961 3308,579 Thams Mar. 14, 1967 3368,306 von Wedel Feb. 13, 1968 3434,238 Muller Mar. 25, 1969 3667,162 Lalague June 6, 1972 3802,124 Guerrini Apr. 9, 1974 3867,790 Frank Feb. 25, 1975 3911,621 McHeffey Oct. 14, 1975. ______________________________________
While the window constructions of the above identified references differ in detail, they are all directed to an assembly which comprises a frame, a pane carrying sash mounted in the frame and means for adjusting the window sash into different conditions of operation, namely, a locked condition, a venting condition and a casement condition.
Certain of the references, notably U.S. Pat. Nos. 3,911,621 and 3,667,162, and perhaps others, disclose advanced structures wherein a single handle controls the operating configuration of the sash and also provides the means whereby the operator may physically move the sash to an inward tilted position for venting and may pivot the sash about a vertical pivot axis where the window is used in a casement mode or for cleaning.
Devices of the type described, and particularly those devices controlled by a single operating handle, function, as does the device of the instant application, by connecting the pivotal operating handle to a drive means or mechanism located within the hollow pane carrying sash component. In the locked position, bars, stops or strike members extend between the sash frame and a fixed frame, precluding relative movement of these parts. When the operating handle is shifted to the venting position, the drive means is actuated to withdraw the locking means from spanning relation of the sash and frame, and functions to engage the components of a pivotal connection whereby the sash may be tilted about a horizontal axis coincident with the lower edge of the sash. Typically, in the venting position the device is provided with means for limiting the inward swinging movement of the sash so that the same cannot fall inwardly. See, for instance, U.S. Pat. No. 3,911,621.
When the device is actuated to a casement condition by rotation of the operating handle, certain of the pivot means which permit pivoting about a horizontal axis are disengaged and a second set of pivot means permitting pivoting about a vertical axis is engaged.
In virtually all of the tilt-turn systems heretofore known, it is intended that actuation of the operating means be effected only when the sash and frame are in coplanar alignment, i.e. in the fully closed position of the window. However, in devices heretofore known it is possible, by rotating the operating handle when the sash is not completely closed, to arrive at an operating condition wherein less than all of the pivoting joints which are intended to interact at a given time are, in fact, engaged. More particularly, where it is sought to shift the window device from the vent position to the casement position, it is intended that the window be completely closed before the operating handle is activated to the desired position. With prior art devices, however, it is possible, where the sash is not completely closed, nonetheless to shift the operating handle to the casement position, with the result that, by virtue of the slight misalignment of the parts, the upper vertical pivot component intended to span the space between the sash and the frame fails to be engaged in the frame. Under such circumstances, the window will be free to pivot simultaneously about a horizontal and a vertical axis and will normally be supported solely at a lower edge portion. Such window will then be prevented from falling inwardly solely by the linkage mechanism disposed between the upper edge of the window and the frame. Since the linkage mechanism is not intended to withstand the stresses applied under such circumstances, it is possible that the linkage may be bent and rendered unusable or, more seriously, that the linkage may break and the window fall inwardly.
Since the sash components of windows of the type described are often extremely heavy, at the very least, should the window be misoperated in the manner noted, the readjustment of the window to its correct operating condition is a most difficult task, often requiring the assistance of the window manufacturer or the installer.
A further common failure in prior windows of the type discussed occurs when the operating handle is rotated while the window is in the casement position before the sash and frame have been disposed in coplanar alignment. Such improper operation may result in the condition hereinabove noted, i.e. sash pivoted both horizontally and vertically and supported solely at the permanent pivot joint and by the motion limiting linkage.